nixpkgs/pkgs/lib/modules.nix
Nicolas Pierron bb16a7f08d Replace a counter intuitive behaviour of module evaluations.
- types.nix:
Introduce a new flag named "delayProperties" which define either that
properties should be evaluated (when false) or that they should be delaied
through the type structure.

- properties.nix:
Generalized the delayProperties function to make it work with the iter
functions of option types.

- modules.nix:
Replace evalProperties by a condition based on the value of the
"delayProperties" flag of the option type.  If the flag does not exists or
if it is false, then the system behaves as always.  Otherwise it delays
the properties from the current value to each values contained inside it.

svn path=/nixpkgs/trunk/; revision=17736
2009-10-09 18:11:30 +00:00

303 lines
8.5 KiB
Nix

# NixOS module handling.
let lib = import ./default.nix; in
with { inherit (builtins) head tail; };
with import ./trivial.nix;
with import ./lists.nix;
with import ./misc.nix;
with import ./attrsets.nix;
with import ./options.nix;
with import ./properties.nix;
rec {
# Unfortunately this can also be a string.
isPath = x: !(
builtins.isFunction x
|| builtins.isAttrs x
|| builtins.isInt x
|| builtins.isBool x
|| builtins.isList x
);
importIfPath = path:
if isPath path then
import path
else
path;
applyIfFunction = f: arg:
if builtins.isFunction f then
f arg
else
f;
isModule = m:
(m ? config && isAttrs m.config && ! isOption m.config)
|| (m ? options && isAttrs m.options && ! isOption m.options);
# Convert module to a set which has imports / options and config
# attributes.
unifyModuleSyntax = m:
let
getImports = m:
if m ? config || m ? options then
attrByPath ["imports"] [] m
else
toList (rmProperties (attrByPath ["require"] [] (delayProperties m)));
getImportedPaths = m: filter isPath (getImports m);
getImportedSets = m: filter (x: !isPath x) (getImports m);
getConfig = m:
removeAttrs (delayProperties m) ["require"];
in
if isModule m then
{ key = "<unknown location>"; } // m
else
{
key = "<unknown location>";
imports = getImportedPaths m;
config = getConfig m;
} // (
if getImportedSets m != [] then
assert tail (getImportedSets m) == [];
{ options = head (getImportedSets m); }
else
{}
);
unifyOptionModule = {key ? "<unknown location>"}: m: (args:
let module = lib.applyIfFunction m args; in
if lib.isModule module then
{ inherit key; } // module
else
{ inherit key; options = module; }
);
moduleClosure = initModules: args:
let
moduleImport = m:
(unifyModuleSyntax (applyIfFunction (importIfPath m) args)) // {
# used by generic closure to avoid duplicated imports.
key = if isPath m then m else "<unknown location>";
};
getImports = m: attrByPath ["imports"] [] m;
in
(lazyGenericClosure {
startSet = map moduleImport (filter isPath initModules);
operator = m: map moduleImport (getImports m);
}) ++ (map moduleImport (filter (m: ! isPath m) initModules));
selectDeclsAndDefs = modules:
lib.concatMap (m:
if m ? config || m ? options then
[ (attrByPath ["options"] {} m) ]
++ [ (attrByPath ["config"] {} m) ]
else
[ m ]
) modules;
moduleApply = funs: module:
lib.mapAttrs (name: value:
if builtins.hasAttr name funs then
let fun = lib.getAttr name funs; in
fun value
else
value
) module;
delayModule = module:
moduleApply { config = delayProperties; } module;
evalDefinitions = opt: values:
if opt ? type && opt.type.delayProperties then
map (delayPropertiesTemplate opt.type.iter opt.name) values
else
evalProperties values;
selectModule = name: m:
{ inherit (m) key;
} // (
if m ? options && builtins.hasAttr name m.options then
{ options = lib.getAttr name m.options; }
else {}
) // (
if m ? config && builtins.hasAttr name m.config then
{ config = lib.getAttr name m.config; }
else {}
);
filterModules = name: modules:
filter (m: m ? config || m ? options) (
map (selectModule name) modules
);
modulesNames = modules:
lib.concatMap (m: []
++ optionals (m ? options) (lib.attrNames m.options)
++ optionals (m ? config) (lib.attrNames m.config)
) modules;
moduleZip = funs: modules:
lib.mapAttrs (name: fun:
fun (
map (lib.getAttr name) (
filter (builtins.hasAttr name) modules
)
)
) funs;
moduleMerge = path: modules:
let modules_ = modules; in
let
addName = name:
if path == "" then name else path + "." + name;
modules = map delayModule modules_;
modulesOf = name: filterModules name modules;
declarationsOf = name: filter (m: m ? options) (modulesOf name);
definitionsOf = name: filter (m: m ? config ) (modulesOf name);
recurseInto = name: modules:
moduleMerge (addName name) (modulesOf name);
recurseForOption = name: modules:
moduleMerge name (
map unifyModuleSyntax modules
);
errorSource = modules:
"The error may come from the following files:\n" + (
lib.concatStringsSep "\n" (
map (m:
if m ? key then toString m.key else "<unknown location>"
) modules
)
);
eol = "\n";
errDefinedWithoutDeclaration = name:
let
badModules =
filter (m: ! isAttrs m.config)
(definitionsOf name);
in
"${eol
}Option '${addName name}' defined without option declaration.${eol
}${errorSource badModules}${eol
}";
endRecursion = { options = {}; config = {}; };
in if modules == [] then endRecursion else
lib.fix (result:
moduleZip {
options = lib.zip (name: values:
if any isOption values then
let
decls = # add location to sub-module options.
map (m:
mapSubOptions
(unifyOptionModule {inherit (m) key;})
m.options
) (declarationsOf name);
in
addOptionMakeUp
{ name = addName name; recurseInto = recurseForOption; }
(mergeOptionDecls decls)
// {
declarations =
map (m: {
source = m.key;
}) (declarationsOf name);
definitions =
map (m: {
source = m.key;
value = m.config;
}) (definitionsOf name);
config = builtins.tryEval
(builtins.toXML (lib.getAttr name result.config));
}
else if all isAttrs values then
(recurseInto name modules).options
else
throw "${eol
}Unexpected type where option declarations are expected.${eol
}${errorSource (declarationsOf name)}${eol
}"
);
config = lib.zipWithNames (modulesNames modules) (name: values_:
let
hasOpt = builtins.hasAttr name result.options;
opt = lib.getAttr name result.options;
values = values_ ++
optionals
(hasOpt && isOption opt && opt ? extraConfigs)
opt.extraConfigs;
in if hasOpt && isOption opt then
let defs = evalDefinitions opt values; in
lib.addErrorContext "${eol
}while evaluating the option '${addName name}'.${eol
}${errorSource (modulesOf name)}${eol
}" (
opt.apply (
if defs == [] then
if opt ? default then opt.default
else throw "Not defined."
else opt.merge defs
)
)
else if hasOpt && lib.attrNames opt == [] then
throw (errDefinedWithoutDeclaration name)
else if any (v: isOption (rmProperties v)) values then
let
badModules =
filter (m: isOption m.config)
(definitionsOf name);
in
throw "${eol
}Option ${addName name} is defined in the configuration section.${eol
}${errorSource badModules}${eol
}"
else if all isAttrs values then
(recurseInto name modules).config
else
throw (errDefinedWithoutDeclaration name)
);
} modules
);
fixMergeModules = initModules: {...}@args:
lib.fix (result:
# This trick avoid an infinite loop because names of attribute are
# know and it is not require to evaluate the result of moduleMerge to
# know which attribute are present as argument.
let module = { inherit (result) options config; }; in
moduleMerge "" (
moduleClosure initModules (module // args)
)
);
}